Valve actuating mechanism



Feb. 20, 1934. D CHURCH 1,948,023

VALVE ACTUATING MECHANI SM Filed Nov. 17, 1951 2 Sheets-Sheet l I w I 40' M m m 1 15 D 30 4 I W Z? J r 33 J i I l/VVENTOR HAROLD E CHURCH. B Y

A TTOR/VEY Feb. 20, 1934. H. D. CHURCH 1,948,023

VALVE ACTUATING MECHANISM Filed Nov. 17, 1931 2 Sheets-Sheet 2 Fi .Z.

1 //v I/ENTOR HAEOZD .2 67/0261! A TTORN -Y Patented Feb. 20, 1934 PATENT OFFICE VALVE ACTUATING MECHANISM Harold D. Church, Cleveland, Ohio, assignor to The White Motor Company, Cleveland, Ohio,

a corporation of Ohio Application November 17, 1931 Serial No. 575,503

4 Claims.

This invention relates to valve operating mechanisms of the type employed in internal combustion engines.

It is an object of this invention to provide a valve operating mechanism which automatically adjusts itself to compensate for thermal contraction and expansion of the valve, the parts of the mechanism, and the parts of the structure M which support it..

H engine crank shaft by mounted in the guide 23 set in the lower flange.

Itisa further object of this invention to provide an improved construction for an internal combustion engine through the use of valve operating mechanism as aboveset forth.

7 Other objects and attendant advantages will appear in the following description when read in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary transverse section I of an internal combustion engine provided with valve actuating mechanism embodying this invention, the section being taken on a line corresponding with line 11 of Figure 3.

Figure 2 is a fragmentary transverse sectional view of the engine, the section being taken on a line corresponding with line 2-2 of Figure 3, and

Figure 3 is a fragmentary top plan view of the engine with the cylinder head cover removed.

Referring to the drawings, the reference numeral indicates an exhaust passage of the engine, and the numeral 11 a'valve for controlling the exhaust passage 10. The valve 11 is mounted in a guide 12 set in the cylinder head 13 of the engine, and is arranged to cooperate with a seat 14 formed in the lower surface of the cylinder head. Secured to the upper end of the valve 11 there is a cup shaped member 15 slidably mounted in a guide 16 secured to the upper end of the cylinder head; and bearing at their opposite ends against the member 15 and the guide 16, there is a pair of valve closing springs 17 and 18.

Journalled in the side of the engine crank case 19 there is a cam shaft 20 driven from the means of a driving connection (not shown). This shaft effects opera tion of the valve 11 through the instrumentality of an integrally formed cam 21, an intermediate train of mechanism comprising a tappet 22 of the engine cylinder block 24, an upwardly extending push rod 25, and a rocker arm 26 mounted upon the upper end of the cylinder head.

Included in the intermediate train of mechanism above described, there is a screw 27 mounted in the end of the rocker arm 26, and formed with a spherical head which fits within a complementary recess in the upper end of'the push rod 25. This screw serves as a means for tightening and loosening the intermediate train of mechanism and is employed in making such adjustments.

The rocker arm 26 is journalled upon a bush ing 28, itself eccentrically journalled upon a shaft 29 supported above the cylinder head by 5, posts 30. The eccentrically mounted bushing 28 is connected to a thermo-responsive mechanism for controlling its angular position, so connected and coordinated with the bushing that expansion and contraction of the mechanism actuates the bushing to raise and lower the pivotal center of the associated rocker arm 26.

The thermo-responsive mechanism which may be described in general as consisting of a steel pin 31 extending through the exhaust passage '10, and an S-shaped steel connecting member 32 extending between the pin and the bushing, is so designed and arranged that the raising and lowering of the pivotal center of the bushing resulting from its expansion and contraction is such as to annul in a large degree the tightening and loosening effects upon the valve actuating mechanism, of the expansion and contraction of the valve 11, the serially associated parts 22, 25, and 26, and the associated parts of the engine.

Returning to the construction of the thermoresponsive mechanism, the connecting member 32 is slidably mounted on the extended end of a cylinder head stud 33, and is pivotally connected to the bushing 28 by means of a pair of arms 34 formed on the bushing, and a cylindrical end portion 35 on the upper end of the member which fits between the arms on the bushing. The steel pin 31 is screwed into the lower wall of the exhaust passage 10, and extends up through the cylinder head through a bore 36 of sumciently large diameter as not to interfere with its thermal expansion and contraction. The upper end of the pin 31 is connected with the lower end of the S-shaped connecting member 32 by means of a flanged collar 3'7 and a washer 38 held upon the pin between an integrally formed flange 39 and a nut 40 screwed onto the end of the pin, the lower end of the S- shaped member being formed with a forked end portion which straddles the collar and fits between the opposing surfaces of the washer and the flanged part of the collar.

The action of the parts 31, 32, and 28 in effecting compensation for the thermal expansion and 1 .1.9

contraction of the valve 11, the parts 22, 25 and 26 and the associated parts of the engine permits the valve actuating mechanism to be adjusted for more quiet, more efiicient operation of the valve than could be realized through the use of a conventional valve actuating mechanism of similar type, not equipped with compensating means; and in addition results in the valve timing, and the distance the valve is open, being maintained more nearly constant.

One method of adjusting the valve actuating mechanism, and the one most easy to perform, is to adjust the mechanism so that it will possess a small, predetermined, minimum amount of slack throughout the range of engine temperatures. Such an adjustment will insure that the valve is not held open by discrepancies in the compensation eifected by the parts 31, 32 and 28, and at the same time will provide for quiet oper ation of the valve.

A convenient method of effecting an adjustment of the valve actuating mechanism, as above described, is to adjust the mechanism at a high engine temperature by means of the screw 27 so as to'possess a certain small amount of slack, and then as the engine temperature falls making such other adjustments as are necessary to keep the amount of slack from falling below that initially adjusted for.

Although I have described my invention in conjunction with the exhaust valve of the engine, it will be understood that it may be successfully employed with the inlet valve of an engine to produce the same result.

It will be further understood that my invention is not limited to the specific construction employed in the herein described embodiment, but is broad enough to comprehend all changes and rearrangements in construction coming Within the scope of the appended claims.

What I claim is: g

1. In an internal combustion engine, the combination of a combustion chamber, an exhaust conduit leading into said combustion chamber, a valve for controlling said conduit, a closing spring for said valve, a rotatable cam, a train of mechanism operable by said cam to open and close said valve including a pivotally mounted rocker arm, and means acting to annul the tightening and loosening efiects of the thermal expansion and contraction of said valve, the parts of said train of mechanism, and the associated parts of said engine, said means comprising an eccentrically rotatably mounted member serving as a journal for said rocker arm, and a thermoresponsive mechanism including a part exposed to the gases ejected through said conduit and operatively connected to said member in such a manner as to effect rotation thereof.

2. In an internal combustion engine, the combination of a combustion chamber, an exhaust conduit leading into said combustion chamber, a poppet valve for controlling said conduit, a closing spring for said valve, a train of mechanism movable to transmit the valve opening and closing movements including a pivotally mounted member, and means for varying the pivotal center of said member acting to annul the tightening and loosening effects upon said train of mechanism of the thermal expansion and contraction of said valve, the parts of said train of mechanism, and the associated parts of said engine, said means including a part extending into said exhaust conduit and exposed to the gases ejected therethrough, and mechanism actuated through the expansion and contraction of said part to vary the pivotal center of the aforesaid member.

3. In an internal combustion engine, the combination of a combustion chamber, an exhaust conduit leading into said combustion chamber, a poppet valve for controlling said conduit, a closing spring for said valve, a train of mechanism movable to transmit the valve opening and closing movements including a member movable with the remaining elements in said train for trans" mitting the valve opening and closing movements, and separably movable to tighten and loosen said train of mechanism, and means acting to annul the tightening and loosening effects or" the thermal expansion and contraction of said valve, the parts of said train of mechanism, and the associated parts of said engine, said means including a part extending into said exhaust conduit and exposed to the gases ejected therethrough, and mechanism connecting said part with the aforesaid member whereby expansion and contraction of said part eifects movement of said member to loosen and tighten said train.

a. In an internal combustion engine, the combination of a combustion chamber, a breathing conduit leading into said combustion chamber, a poppet valve for controlling said conduit, a closingspring for said valve, a train of mechanism movable to transmit the valve opening and closing movements including a member movable with the remaining elements in said train for transmitting the valve opening and closing movements, and separably movable to tighten and loosen said train of mechanism, and means acting to annul the tightening and loosening effects of thermal expansion and contraction of said valve, the parts of said train of mechanism, and the associated parts of said engine, said means including a part exposed to the direct influence of the gases of combustion, and mechanism connecting said part with the aforesaid member whereby expansion and contraction of said part effects movement of said member to loosen and tighten said train.

HAROLD D. CHURCH.

III 

